1. Field of the Invention
This invention relates to oxygen sensors. In one of its more particular aspects, this invention relates to a galvanic electrode oxygen sensor for measuring transcutaneous oxygen pressure. In yet another of its more particular aspects, this invention relates to a temperature compensated oxygen sensor.
Electrodes for measuring transcutaneous pO.sub.2 are useful in various clinical applications. For example, such electrodes can be used in surgery to monitor tissue oxygen during the course of anesthesia, to monitor shock in trauma situations in which there is blood loss or to monitor tissue oxygen pressure in newborn infants to detect respiratory or vascular problems.
2. Prior Art
A glucose-oxygen sensor in which an oxygen-sensitive primary cell consists of a silver cathode, a lead anode and an acidic buffered electrolyte in a flat plastic housing is disclosed in S. P. Bessman and R. D. Schultz, "Prototype Glucose-Oxygen Sensor for the Artificial Pancreas", Trans. Amer. Soc. Artif. Int. Organs, 19:361-364 (1973).
An oxygen-sensitive primary cell in which the cathode is made of thin silver wire tightly wound into a flat spiral with oxygen diffusing through a polypropylene membrane and then through the electrolyte between successive turns of the spiral is described in S. P. Bessman and R. D. Schultz, "Progress Toward a Glucose Sensor for the Artificial Pancreas", in Ion Selective Microelectrodes, H. J. Berman and N. C. Hebert, Eds., pp. 189-197, Plenum Publishing Corporation, New York (1974).
An oxygen electrode in which the skin is heated to maintain constant temperature of the electrode is disclosed in A. Huch, R. Huch, B. Arner and G. Booth, "Continuous Transcutaneous Oxygen Tension Measured with a Heated Electrode", Scand. J. Clin. Lab. Invest., 31:269-275 (1973).
A probe for temperature compensated transcutaneous carbon dioxide measurement in which an error signal is generated by temperature sensor means is disclosed in U.S. Pat. No. 4,301,807 to R. A. Mentelos, Nov. 24, 1981.
An implantable glucose sensor having an electrical circuit for making corrections for temperature and oxygen concentration is disclosed in U.S. Pat. No. 4,431,004, to S. P. Bessman, E. C. Layne and L. J. Thomas, Feb. 14, 1984.
Although the above references relate to various techniques for measuring oxygen, glucose and carbon dioxide, none provides a convenient means for measuring pO.sub.2 transcutaneously at ambient temperature with a conveniently manufactured sensor that may be disposable.
3. Objects
The principal object of the present invention is to provide a convenient means for measuring transcutaneous pO.sub.2 .
Another object of this invention is to provide such a means which does not require the heating of the skin of the patient whose pO.sub.2 is being measured.
Another object of this invention is to provide a transcutaneous oxygen sensor which can be manufactured conveniently.
Another object of this invention is to provide a transcutaneous oxygen sensor which is disposable.
Other objectives and advantages of the present invention will become apparent in the followed detailed description.